Proof of concept: The vacuum transfer in pictures (I)
The first complete test run of the new vacuum transfer unit had had to be postponed a number of times, but yesterday Wolfram Calvet and Karsten Prietzel finally got their chance - and they used it.
Here they maneuver the transfer unit into the lab to connect it to the deposition unit where the chalcopyrite absorbers are made. As in most labs, space is a limited resource, and the long transfer rods don't make things any easier...
Karsten Prietzel, who designed the entire construction, admits: "I didn't sleep very well last night. I really hope this is going to work."
As a precaution, they have to wear particle filter masks while handling the open deposition unit to protect them against Selenium and other stray atoms. They are placing the substrate holders in the vapor chamber.
The one with the small square inlay is the one this is all about. Only the small square will fit into the CISSY-system. This is the part that needs to be grabbed and transferred onto a new substrate holder and into the transfer unit.
The new substrate holder has to be put into position. The only way to move anything within the vacuum system is by the long transfer rods. It takes patience and some practice to adjust to this kind of "remote" handling. Especially with things as small and delicate as these. And then - at some point - it still has to be the first time.
Once all is in place, Karsten Prietzel starts the deposition process. The chamber is heated to different temperatures and Gallium, Indium, Selenium and Copper are vaporised and deposited on the little wavers according to a very specific protocol.
While the chamber is heating up, the team goes for lunch.